Benâ€™s class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?

How will you work out which numbers have been used to create this multiplication square?

Use this grid to shade the numbers in the way described. Which numbers do you have left? Do you know what they are called?

Can you see why 2 by 2 could be 5? Can you predict what 2 by 10 will be?

Can you each work out the number on your card? What do you notice? How could you sort the cards?

A game for 2 people using a pack of cards Turn over 2 cards and try to make an odd number or a multiple of 3.

Use the information about Sally and her brother to find out how many children there are in the Brown family.

There is a clock-face where the numbers have become all mixed up. Can you find out where all the numbers have got to from these ten statements?

This problem is based on a code using two different prime numbers less than 10. You'll need to multiply them together and shift the alphabet forwards by the result. Can you decipher the code?

This article for teachers describes how modelling number properties involving multiplication using an array of objects not only allows children to represent their thinking with concrete materials,. . . .

The clockmaker's wife cut up his birthday cake to look like a clock face. Can you work out who received each piece?

Suppose we allow ourselves to use three numbers less than 10 and multiply them together. How many different products can you find? How do you know you've got them all?

Take the number 6 469 693 230 and divide it by the first ten prime numbers and you'll find the most beautiful, most magic of all numbers. What is it?

Does this 'trick' for calculating multiples of 11 always work? Why or why not?

Can you find different ways of creating paths using these paving slabs?

The Man is much smaller than us. Can you use the picture of him next to a mug to estimate his height and how much tea he drinks?

A game for 2 people. Use your skills of addition, subtraction, multiplication and division to blast the asteroids.

If you had any number of ordinary dice, what are the possible ways of making their totals 6? What would the product of the dice be each time?

Use your logical-thinking skills to deduce how much Dan's crisps and ice-cream cost altogether.

Your vessel, the Starship Diophantus, has become damaged in deep space. Can you use your knowledge of times tables and some lightning reflexes to survive?

What is the lowest number which always leaves a remainder of 1 when divided by each of the numbers from 2 to 10?

This article for teachers looks at how teachers can use problems from the NRICH site to help them teach division.

How would you find out how many football cards Catrina has collected?

This problem is based on the story of the Pied Piper of Hamelin. Investigate the different numbers of people and rats there could have been if you know how many legs there are altogether!

Here are the prices for 1st and 2nd class mail within the UK. You have an unlimited number of each of these stamps. Which stamps would you need to post a parcel weighing 825g?

The Scot, John Napier, invented these strips about 400 years ago to help calculate multiplication and division. Can you work out how to use Napier's bones to find the answer to these multiplications?

This task offers an opportunity to explore all sorts of number relationships, but particularly multiplication.

Here is a picnic that Petros and Michael are going to share equally. Can you tell us what each of them will have?

If the numbers 5, 7 and 4 go into this function machine, what numbers will come out?

Twizzle, a female giraffe, needs transporting to another zoo. Which route will give the fastest journey?

Here is a chance to play a version of the classic Countdown Game.

This task combines spatial awareness with addition and multiplication.

This challenge combines addition, multiplication, perseverance and even proof.

Four Go game for an adult and child. Will you be the first to have four numbers in a row on the number line?

How will you decide which way of flipping over and/or turning the grid will give you the highest total?

In November, Liz was interviewed for an article on a parents' website about learning times tables. Read the article here.

Look at what happens when you take a number, square it and subtract your answer. What kind of number do you get? Can you prove it?

After training hard, these two children have improved their results. Can you work out the length or height of their first jumps?

How would you count the number of fingers in these pictures?

Find the next number in this pattern: 3, 7, 19, 55 ...

Go through the maze, collecting and losing your money as you go. Which route gives you the highest return? And the lowest?

What do you notice about the date 03.06.09? Or 08.01.09? This challenge invites you to investigate some interesting dates yourself.

Can you design a new shape for the twenty-eight squares and arrange the numbers in a logical way? What patterns do you notice?

Amy has a box containing domino pieces but she does not think it is a complete set. She has 24 dominoes in her box and there are 125 spots on them altogether. Which of her domino pieces are missing?

Number problems at primary level that require careful consideration.

Number problems at primary level that may require resilience.

This number has 903 digits. What is the sum of all 903 digits?

Using the statements, can you work out how many of each type of rabbit there are in these pens?